Contrast Reversals of Pseudo-Kikuchi Band and Lines Due to Detector Position in Scanning Electron Microscopy

Abstract

The contrast reversals of pseudo-Kikuchi band and lines due to the detector position are observed for Si by using the surface scanning electron microscope. The detector is placed at two positions, i. e. high and low angle positions for the crystal surface. In the high angle detection, the pseudo-Kikuchi band changes its contrast from excess to defect with decreasing the glancing angle and moreover the contrast of Kikuchi lines is also reversed between a pair of lines and along a line in the region of the low glancing angle. These situations are not observed in the low angle detection. These facts are explained qualitatively by applying the reciprocity theorem in electron diffraction and the dynamical theory of two-beam approximation with considering the anomalous absorption and the angular distribution of inelastic scattering electrons in crystal.